For camping and other recreational activities, different hammocks have been developed to provide shelter from insects, ground dwelling creatures and inclement weather. Being suspended above the ground, hammocks provide a more comfortable, dry, warm and clean surface than do tents.
Traditional hammocks were entered by climbing over one side. That was difficult and sometimes dangerous, because the hammock was out of balance when a person entered it. The potential occupant pushed down one of the higher sides of the hammock, as low as possible, towards its longitudinal axis of symmetry, to gain access. As soon as the person sat down and his weight came off of his feet, the hammock swung back into its original position, tumbling the person backward, sometimes out of the hammock.
In my U.S. Pat. No. 6,185,763—the disclosure of which is incorporated herein by reference—I described a hammock which had a partial entrance slit running from one end of the hammock about half the hammock length, so that one could enter the hammock simply by standing up through the slit from directly beneath one end of the hammock, and then reclining on the unslit portion of the bed. The person's weight induced lengthwise tension in the fabric, which closed the slit so well that he or she could lie right on the slit and not fall out. I thought at the time that the slit must extend along the longitudinal center plane of the hammock, where the tension forces are the greatest.
My U.S. Pat. No. 6,865,757—which is also incorporated herein by reference—discloses a different hammock which is asymmetrical so as to encourage one to lie not along the tension axis established by the ropes at either end, as one does in most hammocks, but rather diagonally across the tension axis. This improves comfort by enabling one to lie diagonally across the tension axis.
I have combined the features of these two concepts, by making hammocks which have a bottom entrance slit and which are asymmetrical. These hammocks work as expected, but some users have reported that—particularly in asymmetrical versions where they lie diagonally to the longitudinal direction—lying across the tensioned slit is uncomfortable.
Knowing that fabric tension under load is the greatest along the center line of a hammock, I had thought that the slit would have to be centered in the hammock material for it to work; however, I have discovered that, when the occupant changes position from the longitudinal axis to lie on a diagonal axis, tension of the bottom fabric is spread over a wider area, allowing the entrance slit to remain under tension even when offset to one side of the longitudinal axis of the hammock. Moreover, the offset slit will remain closed under tension against all but deliberate opening maneuvers.